Two women accused of killing the half-brother of North Korea's leader have pleaded not guilty as their trial started in Malaysia.

LATEST: Malaysian authorities have made two more arrests over the death of the North Korean leader's half-brother, who was reportedly poisoned by a pair of female assassins as he waited for a flight in Kuala Lumpur.

A second woman has been arrested in connection with the killing of North Korea leader Kim Jong Un's half brother at a busy airport.